Okay, so now I'm convinced I've got low blood sugar (hypoglycaemia).
I seem to be ticking many of the boxes.
Always starts in the morning, and I feel weak, nervous, hungry but little appetite, fatigued. During the morning I'll get sweaty hands, the nervousness and weakness continues with a light headed feeling and sometimes feel like I could pass out.
Edit: oh, and forget, also get weakness and fatigue after exercising (not during though).
It tends to go away if I eat small amounts frequently and drink soft fruit drinks. I'll often be fine by the evening, but it starts over again in the morning (obviously having not eaten anything overnight).
Of course, the more I dwell on it the worse things seem to get.
I want to get some kind of test, but earliest I can see my doc is not until next Thursday, and besides I just get sent away with "it's just anxiety" most of the time.